As a dispenser attached to a mouth of a container containing a liquid, such as an antimold, a detergent, a sizing agent for textiles, household wax, a hair liquid, and an aromatic, a trigger-type liquid dispenser is widely used. Such a trigger-type liquid dispenser may dispense the liquid through a nozzle in the form of spray or foam with use of a pump configured to be actuated in response to operation of a trigger.
Such a trigger-type liquid dispenser also includes a dispenser main body fitted to the mouth of the container by, for example, a fitting cap, and the dispenser main body is provided with a flow path communicating with the container, and the nozzle is fitted on the downstream side of the flow path. The pump is connected to the midway of the flow path, and, when the pump is actuated, the liquid contained in the container is pressure-fed along the flow path and dispensed to the outside through the nozzle.
Furthermore, such a trigger-type liquid dispenser, as commonly used, includes a pump including a cylinder and a piston. In this case, the piston is provided, on an outer circumferential surface thereof, integrally with a sealing piece, which protrudes to the outer side in the radial direction from the outer circumferential surface and which is in sliding contact with an inner circumferential surface of the cylinder for sealing between the cylinder and the piston. The piston also has a front-side end portion engaged with the trigger, and, as the trigger is operated, the piston is pushed into the cylinder to pressure-feed the liquid to the flow path. (Refer, for example, to Patent Literature 1.)